But there is a bug in which the level loses all its data. This a pretty critical bug. You can see the bug report here (and I encourage you to vote for it) Unreal Engine Issues and Bug Tracker (UE-75254)
So I wonder what’s the official method to build lighting using level streaming since unhiding levels and building invalidates the data of all the hidden levels, and building the lighting of each level separately in their corresponding persistent level works, but it is automatically invalidated once you open the persistent level in which it is a sublevel
Its a pity there are no replies to this, I am having the same problem.
Building lighting on streaming level loaded by itself (dumpunbuilt = 0)
Building lighting on persistent level without any streaming maps loaded (dumpunbuilt = 0)
turn on streaming map from persistent map (dumpunbuilt = 1)
What happens if you build the light in separate levels, don’t open anything at all, in fact, open a new blank level. Package the project out, and try to play?
is the light ok or is it still essentially not built once the regular level loads?
Hardly a workaround if it works - but at least you can publish I guess.